alright guys, this thread is turning the wrong way as so many do
the fact of the matter is that this is a bit of a non issue anyway. BA operate 57 747s (i.e. 228 engines + spares) and the 757/767 fleet are also powered by the RB211, so god knows how many in total. Now try and estimate how many millinons of trouble free hours these engines perform, they are an engineering miracle, tried and tested and certified and fitted to thousands of aircraft around the world. Now think how many have had this small problem associated with them. I think you'd be struggling to find a figure above 1%.
For sake of a minor issue, the media will read it as "BA JUMBOS NOT SAFE TO FLY ON, ENGINES WILL STOP"........
torquelink, I will ask the engine guys in work about your questions, that's a bit beyond my knowledge as I'm an avio!
Sorry gaspath, I stand corrected - I was under the impression that the -400 fleet was all trent core now.